This K23 application is a request for the support to assist Dr. Lee Morrow's development into an independent, patient-oriented researcher with expertise in nosocomial pneumonia. Although the candidate has formal training in pulmonary medicine, critical care medicine, clinical research design, and statistical analysis, his transition to becoming an independent researcher in this field would benefit greatly from structured integration of these skills. Dr. Morrow's short-term goals are to improve his core content knowledge of medical microbiology and infectious diseases, to refine his statistical and methodological skills, and to use the mentored completion of a large clinical trial as a vehicle for obtaining invaluable practical experience and professional development. The candidate's long-term goals are to develop into an independent investigator funded by external sources, to train and mentor future clinical researchers, and to develop a network of research scientists devoted to optimizing the prevention and treatment of nosocomial pneumonia. Drs. Thomas Casale and Marin Kollef, established investigators and internationally renowned thought leaders, will serve as Dr. Morrow's mentor and co-investigator respectively. During the proposed period of study, Dr. Morrow will assess the effectiveness of a novel strategy to prevent ventilator associated pneumonia. Specifically, the proposed research will examine whether oral and gastric administration of the probiotic agent Lactobacillus caseii subspecies rhamnosus to intubated patients: (1) preserves normal oral flora;(2) prevents oral overgrowth of pathogens;(3) prevents gastrointestinal tract and bronchoalveolar colonization;and (4) reduces ventilator associated pneumonia rates. The proposed research will provide clinically relevant information while serving as the foundation for Dr. Morrow to develop novel avenues of future research. Creighton University's Center for Practice Improvement and Outcomes Research (CPrlOR) and the Center for Research on Anti-lnfectives and Biotechnologies (CRAB) make this institution an ideal environment for the completion of this project.